Explanation:
Sometimes it looks like the Sun is being viewed through a large
lens.
In the above case, however, there are actually millions of lenses:
ice crystals.
As water freezes in the upper
atmosphere, small, flat, six-sided, ice crystals might be formed.
As these crystals flutter to the ground, each
crystal
can act like a miniature lens, refracting sunlight into our view.
The above image was taken near sunset last month near Nashville,
Tennessee,
USA.
Dramatically visible behind neighborhood houses and trees and above the cloud deck is the
22 degree halo created by
sunlight refracting off of atmospheric ice crystals.